63 F.I. troubles

[rudy]

I"m looking for guidance in correctly setting up my 63 F.I. car. ever since sending out the unit for rebuild the car has performed poorly,i.e. starts hard, backfires & breaks down @5500rpm. any suggestions would be helpful.

[Bill W.]

Re: 63 F.I. troubles

Howdy Rudy,


Your FI may have been bitten by the Y2K bug! But a more likly explanation is a bad cranking signal valve. All of the major FI rebuilders do a fine job of sitting the units up, so I think chances are slim that anything big is wrong with your unit.


Remove your CSV from the enrichment dia. cover and suck lightly on the threaded end, you should be able to pull air through the valve. Now suck hard on it, the valve should close and not leak.


You may temporarly remove the CSV from the system also. Try this, and if the unit runs better, you have found your problem.


You mention cutting out at 5500 rpm, this may be a seperate problem. Sounds like the "rich stop" may be a tad on the lean side. For now, check the CSV and lets see if that fixs some of it. Bill

[Chuck G.]

Re: 63 F.I. troubles

I've recently become aware that some of the rebuilt/redetailed/replated units have problems sealing in the areas of the control diaphragm and the enrichment diaphragm. Apparently in the plating process, heat is used and some of the covers warp. Thus the diaphrapms don't "seal" properly. Remove the main control and enrichment diaphragm covers and check for straightness on a piece of glass. Also, be sure to give the cranking signal valve the "suck" test, and see if it holds vacuum. And finally, make sure that you have no vacuum leaks. The FI units need a lot of vacuum to operate properly..16 to 18 inches of HG as I recall. You didn't change the cam, did you? Hope this helps. Chuck

[Bill Clupper]

Re: 63 F.I. troubles

In addition to the checks noted by the other posters, a complete "Tune-up" is recommended with a new FI. The FI is much more particular about old plugs and piints than the carbureted cars are. By the way, an easy way to check the seal of the diaphrams without disassembling the unit is to use a hand-held vacuum pump, and attach the pump to the vacuun side of each diaphram, pump a small vacuum, and see if it holds. A good seal should hold vacuum in this test almost completely. If nothing else, this might lead you to finding the correct cover to use Chuck's process on.